Method of incorporating gas into clay slurries



Patented May 9, 1950 2,501,131 7 METHOD OF mcoaroaarme GAS MO I I CLAY sLuaRms Judith Winston and Frances L. Weinstein, Houston, Tex., assignors to Standard Oil Development Company, a corporation of Delaware A No Drawing. Application April 4, 1946,

Serial No. 659,660

4 Claims. (Cl. 106 40) The present invention is for producing mineral suspensions of. light weight.

The present invention is based on the discovery that certain esters of polvghosphoric acids have the property facilitating the incorporation of air or other gas into mineral suspensions particum where these suspensions include colloidal material. These esters make possible the production of cla mixes, for example, containing large quan 1 ms of air or other gas in the form of minute bubbles of high stability. They also have a similar effect on cement and concrete 'mixes. Where the mix to he aerated is 001101- dally inert, small quantities of colloidal material, phosphoric acid.

such as bentonite 9r starch, may be incorporated in the mix together with the ester.

directed to a method I 4 erating effect of these esters, a suspension of fi'eifi' The particular esters which have been found suitable for this purpose are the all h of the oly hos horic acids of which pyrophosphori'c acid is the first memher. Both the md'no- 10 a polyhydric alcohol esters may he empi oyed, although the former are preferred. These esters are preferably employed in the form of their alkali metal salts.

In practicing the present invention, the mineral to be embodied in an aerated suspension is employed in a finely divided state. It is mixed with water to form a highly viscous mixture or mobile paste, small quantities of the ester are incorporated and the mixture 'lntl a ted while being expose d to air gr tl e g as to be incorporated. The mixture fiufi's upand assumes the appearance of whippedgr eam or other aer- The more via ent'theagitation andTlie onger it is continued the finer will be the bubbles of gas entrained in the mix. These bubbles are very stable.

Among the esters which are suitable for the practice of the present invention may be mentioned Eiethyl ammonium tri lyphosphate, triethyl ammomum "t'etraphosphate, penta ethyl potassium npo yp osp a e. e preceding and renew- Wu'mf the esters embraced in this invention, it is to be understood that the compounds referred to are esters in hich one of the ester substituents is replaced with an alkali .me a. us, as herein use the termino ogy penta capryl potassium tripolyphosphate refers to a tripoly phosphate ester in which all substitutable hydrogen atoms are replaced with a single potassium atom and capryl radical. The

- compound may be considered to be the alkali metal salt of the penta capryl ester of tripoly- In a typical demonstration of the ceramwfla edfithining 30% clay in water was prepare This suspension had a viscos ty of about 30 cp. as measured on the Stormer viscosimeter at 600 R. P. M. .01 gram of penta capr l potassium tripolyphosphate was added 66 I60 cos. of the suspension an e mixture stirred on a high speed stirrer while {3pm Large quantities of air were en rained in the mixture and its viscosity increased to 84 cp. Additional increments of the phosphate were added with high speed stirring until .08 gram of the phosphate was incorporated in the mix. At this point the mixture had a viscosity of cps. and was in the form of a stiff gel in which were entrained minute bubbles om e quantity of air enthained mefiegaugea from the fact that the density of the suspension before the treatment with the chemical and stirring was 9.65 pounds per gallon and after the incorporation of .08 gram of the phosphate with high speed stirring the density was 6.08 pounds per gallon. It may be mentioned that the limit of entrainment of air had not been reached as the curve had a sharp upward trend after the last addition of phosphate.

It will be understood that this example is given only to demonstrate the airiiying powers of the chemical. In actual practice much heavier suspensions of clay .will be employed where the production of cast articles is desired.

In order to increase the bonding power of the mix, it is desirable to incorporate in it a highly colloidal material such as Wyoming bentonite.

The inclusion of this material also increases if? airifying power of the chemical. For example, .08 gram of penta octyl potassium tripolyphosphate increased the viscosity of the 30% suspension of ceramic clay previously mentioned from 20 to 100 cp., while the same amount of the same ester increased the viscosity of a 20% suspension of the same ceramic clay containing about 4% by weight of Wyoming bentonite from 35 cp. to 160 op. The mix containing the colloidal material is considerably more stable in its airified form than the less colloidal mix. 7

A thick slurry of Florida Portlang! cement in water containing 40% by weight of the water mhoroughly mixed. It had a density of 16.15 pounds per gallon. To this mix was added 0.4%

by weight of enta gapryl tripolyphosphate. After agitation or three minu es in e presence of air, the sity of the mixture was reduce 1,375'pounds per gallon. This was without any deliberate injection of air or other gas into the to the mixture a small amount of an ester of tripolyphosphoric acid in which one hydrogen atom is replaced by an alkali metal and the remainder of the hydrogen atoms have been reacted with an esterifying alcohol ROI-l where R is an aliphatic hydrocarbon radical having up to 8 --carbon atoms, and agitating said mixture viomix, but only with exposure of the mix to air. Much greater reductions in density can be secured by suitably jetting air or other gas into the mix during the stirring or iiiiifirmt stirring.

. I A 40% slurry of Florida Portland cement, in

which had been incorporated 2% by weight highly colloidal Wyoming bentonite had a density of 16.0 pounds per ga on prior to treatment with the phosphate esters.

After addition of penta capryl potassium tripolyphosphate to the extent of 0.4% of the slurry weight and agitating for three minutes, the density was reduced to 13.3

pounds per gallon. The corresponding specific gravities of completely hydrated and set briquettes of a similarly treated and untreated slurry were found to be 1.48 and 1.92, respectively.

The nature and objects of the present invention having been fully described, what we desire to claim is:

1. A method for incorporating gas into an aqueous mixture of clay which comprises adding lently in the presence of a gas to be incorporated.

2. The method of claim 1 in which the said ester is a capryl ester of tripolyphosphoric acid.

3. The method of claim 1 in which the said ester is an octyl ester of tripolyphosphoric acid. 4. A method for incorporating gas into an aqueous mixture of clay which comprises adding REFERENCES CITED The following references are of record in the file of this patent:

-UNITED STATES PATENTS Number Name Date 1,782,383 Greider Nov. 18, 1930 2,176,078 Katzman Oct. 17, 1939 2,190,769 Butz Feb. 20, 1940 Hochwalt Mar. 19, 1940 

1. A METHOD FOR INCORPORATING GAS INTO AN AQUEOUS MIXTURE OF CLAY WHICH COMPRISES ADDING TO THE MIXTURE OF SMALL AMOUNT OF AN ESTER OF TRIPOLYPHOSPHORIC ACID IN WHICH ONE HYDROGEN ATOM IS REPLACED BY AN ALKALI METAL AND THE REMAINDER OF THE HYDROGEN ATOMS HAVE BEEN REACTED WITH AN ESTERIFYING ALCOHOL ROH WHERE R IS AN ALIPHATIC HYDROCARBON RADICAL HAVING UP TO 8 CARBON ATOMS, AND AGITATING SAID MIXTURE VIOLENTLY IN THE PRESENCE OF A GAS TO BE INCORPORATED. 